The present invention relates to a system and method for controlling the pressure in a distribution network for distribution of fluids. The fluids may be drinking water, gas, or water based district heating by way of example.
The invention, in particular, relates to a system and method for controlling the pressure in a distribution network with changing flow conditions.
In fluid distribution networks such as mains water distribution networks the pressure is normally created by pumps. However, the pressure may also be created by the gravity head of water in a water tower or another reservoir and then the pressure may be regulated by valves.
In mains water distribution networks the pressure in the arterial supply pipes is significantly higher than the pressure required by the consumers (the end-user). The pressure is traditionally created by the use of a pump station that may comprise several pumps. In order to provide the required pressure at the consumer, the pump station traditionally builds up a pressure that is larger than the required pressure because the provided pressure is required to exceed a predefined minimum pressure (typically 2 bar) at the consumers under all conditions. Typically a pump station is configured to deliver a pressure according to a fixed constant pressure curve that is chosen so that the provided pressures at the consumers exceed the required minimum pressure. This regulation strategy ensures that the required pressure is provided constantly, however, a huge amount of energy and fluid (through fluid leakage) is typically wasted. In a water distribution system, the manager of the waterworks knows what pressure is needed when the flow is at its maximum. However, the manager does not always know the exact value of the maximum flow.
Due to changing flow and pressure conditions in a distribution network the actual pressure typically exceeds the required pressure most of the time. This “too high” pressure may cause leakages in the distribution network causing fluid losses and pipe breakdown.
It is desirable to specify a system and method for controlling the pressure in a distribution network in which the fluid losses can be minimised without violating the performance.
It is also desirable to specify a system and method for controlling the pressure in a distribution network that is capable of automatically adapting to actual pressure and/or flow conditions in the network.